Torque converters are commonly used to couple engines to automatic transmissions. Torque converters generally include a pump that is coupled to the engine and a turbine that is coupled to the automatic transmission. As the engine rotates the pump, fluid from the pump turns the turbine. In turn, the turbine rotates an input shaft of the automatic transmission.
Torque converters can suffer certain drawbacks. For example, as a rotational velocity of the turbine approaches a rotational velocity of the pump, a torque increase provided by the torque converter decreases. The torque increase can approach zero when the rotational velocity of the turbine is about eighty-five percent of the rotational velocity of the pump in certain torque converters. As another example, the fluid coupling between the pump and turbine can limit torque transfer between the engine and automatic transmission. To avoid such torque transfer limits, certain torque converters include a clutch that connects the pump and turbine together. The clutch may be closed when an associated vehicle is traveling at constant velocities.
When the clutch is closed, the engine is directly coupled to the automatic transmission via the clutch. However, torsional vibrations between the engine and automatic transmission can negatively affect performance of an associated vehicle when the clutch is closed. Certain torque converters include coil spring dampers that assist with damping torsional vibrations within the torque converters. However, such coil spring dampers are generally tuned to specific frequencies and offer limited dampening outside of the tuned frequencies.
Accordingly, a torque converter with features for damping torsional vibrations within the torque converter across a wide range of frequencies would be useful. In particular, a torque converter with features for tuning a damping coefficient of the torque converter for a wide range of torsional vibration frequencies within the torque converter would be useful.